Ginned cotton bales conventionally come from the gin in standard so-called "flat" bales measuring approximately 25.times.45.times.55 inches, tied around the shorter sides by 124-inch baling wires, and having a density of about 10-12 pounds per cubic foot. Since bales this size are considered too bulky for efficient transportation and handling, flat bales are normally compressed prior to shipping in a bale press. The bale press, applying a force of about four million pounds, reduces the 45 inch dimension by at least half to produce a compressed bale having over twice the density of the "flat" bale. Two old patents to S. J. Webb, Nos. 659,612 and 677,148, show bale presses typical of those still used today.
Flat bales are conventionally pressed and re-tied by the following procedures:
1. The flat bales (FIG. 1a) are first slightly compressed (FIG. 1b) in a small device called a "dinky" press. This reduces the height of the bale just enough to relieve tension on the 124-inch baling wires so that they can be severed by means of a hand-operated wire cutter. The wires are removed and set aside for re-use.
2. The bale covers are then tied with string to stabilize the bale while it is being transported to the press.
3. The flat bale is inserted between the top and bottom platens of a large press operated by a steam or hydraulic cylinder (FIG. 1c).
4. Two opposing pivoted doors are brought from an initial horizontal position to vertical, confining the bale within a twenty-four inch space equal to the width of the platens.
5. The platens are then drawn together with a force rising to approximately four million pounds (FIG. 1d), whereupon the original height of 45 inches is reduced to about twelve inches.
6. With the bale thus compressed, the doors are lowered back to horizontal (FIG. 1e), enabling workers standing on the doors to re-tie the compressed bale with shortened, straightened 84-inch wires (FIG. 1g) salvaged from step #1. The shortened wires are passed around the compressed bale through transverse grooves specially provided in the platens, as shown for example in FIG. 1 of the Webb U.S. Pat. No. 659,612 or in FIG. 1 of U.S. Pat. No. 4,320,701 to Donaldson. (The latter patent shows conventional loop ends used for uniting the ends of the baling wires. Looped connections fail suddenly, without slippage, and have approximately an 1800-pound load limit, even though the 10-gauge wires from which they are formed have 3000-pound strength.)
7. The wire salvage procedure is a significant subroutine involving steps of (a) cutting the wires to length, (b) straightening them in a machine, (c) forming new loops at the ends thereof, (d) bundling and transporting the wires to the bale press, and (e) disposing of excess.
The total labor force required to compress flat bales in a cotton warehouse is sixteen to eighteen workers (not counting those involved in handling and transporting the bales). Besides the press operator, at least four people are required to re-tie the bales. The others are engaged in operating the dinky press, installing string, or salvaging and reforming the baling wires. A substantial saving in labor costs could be realized by simplifying the retying and salvage operations. This has previously been noted. For example, Webb, in his U.S. Pat. No. 677,148, entitled "Method of Compressing Bales without Removing the Bands", recognized even in 1900 that considerable savings could be achieved by not having to replace the flat bale's original bands. (Today, bands have largely been replaced by 10-gauge wires.)
In view of today's higher labor costs, it is now even more desirable to reduce the still labor-intensive process of recompressing "flat" cotton bales.
A primary object of this invention is therefore to provide a machine for the cotton warehouse industry to re-tie cotton bales as they are being compressed for shipment, using the gin-installed tie wires without removing them from the bale at any time.
Another object of this invention is to provide a knot in each of the ties of the compressed re-tied bales that will yield slightly under excess tension without parting, thereby preventing the original gin installed knot from parting or snapping suddenly when the bale is dropped or swells.
A further object of this invention is to eliminate the necessity for workers to stand near or on moving parts of the press for the purpose of re-tying the bale, since the bales, as received from the gin, can be pressed and re-tied mechanically using this invention.
A further object is to reduce the number of operations that must be performed manually in the compression and re-tying of bales, thereby lowering the compression costs and making it easier to operate multiple shifts with fewer workers.
An important and useful discovery of this invention is the fact that pressure applied to conventionally ginned cotton bales sufficient to square the corners causes the wire ties to buckle outward in a column type elastic deflection that is uniform. This discovery is helpful in securing the wire so that the slack can be removed as the bale is being compressed.